text: // Copyright (c) 2014-2018 The Cedicoin Core developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #include <crypto/hmac_sha256.h>
  
  #include <string.h>
  
  CHMAC_SHA256::CHMAC_SHA256(const unsigned char* key, size_t keylen)
  {
      unsigned char rkey[64];
      if (keylen <= 64) {
          memcpy(rkey, key, keylen);
          memset(rkey + keylen, 0, 64 - keylen);
      } else {
          CSHA256().Write(key, keylen).Finalize(rkey);
          memset(rkey + 32, 0, 32);
      }
  
      for (int n = 0; n < 64; n++)
          rkey[n] ^= 0x5c;
      outer.Write(rkey, 64);
  
      for (int n = 0; n < 64; n++)
          rkey[n] ^= 0x5c ^ 0x36;
      inner.Write(rkey, 64);
  }
  
  void CHMAC_SHA256::Finalize(unsigned char hash[OUTPUT_SIZE])
  {
      unsigned char temp[32];
      inner.Finalize(temp);
      outer.Write(temp, 32).Finalize(hash);
  }
  